From adfefa527a32e711c1bea9c1ac32c20e9cce0660 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Fri, 4 Sep 2015 23:57:25 +0200 Subject: Issue #23517: Fix implementation of the ROUND_HALF_UP rounding mode in datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp(). microseconds sign should be kept before rounding. --- Lib/datetime.py | 48 ++++++++++++++++++++-------------------------- Lib/test/datetimetester.py | 12 ++++++++++-- Lib/test/test_time.py | 13 +++++++------ Python/pytime.c | 8 ++++---- 4 files changed, 42 insertions(+), 39 deletions(-) diff --git a/Lib/datetime.py b/Lib/datetime.py index 5ba2ddb..3bf9edc 100644 --- a/Lib/datetime.py +++ b/Lib/datetime.py @@ -1374,28 +1374,34 @@ class datetime(date): return self._tzinfo @classmethod - def fromtimestamp(cls, t, tz=None): + def _fromtimestamp(cls, t, utc, tz): """Construct a datetime from a POSIX timestamp (like time.time()). A timezone info object may be passed in as well. """ - _check_tzinfo_arg(tz) - - converter = _time.localtime if tz is None else _time.gmtime - - t, frac = divmod(t, 1.0) + frac, t = _math.modf(t) us = _round_half_up(frac * 1e6) - - # If timestamp is less than one microsecond smaller than a - # full second, us can be rounded up to 1000000. In this case, - # roll over to seconds, otherwise, ValueError is raised - # by the constructor. - if us == 1000000: + if us >= 1000000: t += 1 - us = 0 + us -= 1000000 + elif us < 0: + t -= 1 + us += 1000000 + + converter = _time.gmtime if utc else _time.localtime y, m, d, hh, mm, ss, weekday, jday, dst = converter(t) ss = min(ss, 59) # clamp out leap seconds if the platform has them - result = cls(y, m, d, hh, mm, ss, us, tz) + return cls(y, m, d, hh, mm, ss, us, tz) + + @classmethod + def fromtimestamp(cls, t, tz=None): + """Construct a datetime from a POSIX timestamp (like time.time()). + + A timezone info object may be passed in as well. + """ + _check_tzinfo_arg(tz) + + result = cls._fromtimestamp(t, tz is not None, tz) if tz is not None: result = tz.fromutc(result) return result @@ -1403,19 +1409,7 @@ class datetime(date): @classmethod def utcfromtimestamp(cls, t): """Construct a naive UTC datetime from a POSIX timestamp.""" - t, frac = divmod(t, 1.0) - us = _round_half_up(frac * 1e6) - - # If timestamp is less than one microsecond smaller than a - # full second, us can be rounded up to 1000000. In this case, - # roll over to seconds, otherwise, ValueError is raised - # by the constructor. - if us == 1000000: - t += 1 - us = 0 - y, m, d, hh, mm, ss, weekday, jday, dst = _time.gmtime(t) - ss = min(ss, 59) # clamp out leap seconds if the platform has them - return cls(y, m, d, hh, mm, ss, us) + return cls._fromtimestamp(t, True, None) @classmethod def now(cls, tz=None): diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py index f516434..58873af 100644 --- a/Lib/test/datetimetester.py +++ b/Lib/test/datetimetester.py @@ -668,6 +668,8 @@ class TestTimeDelta(HarmlessMixedComparison, unittest.TestCase): eq(td(milliseconds=-0.6/1000), td(microseconds=-1)) eq(td(seconds=0.5/10**6), td(microseconds=1)) eq(td(seconds=-0.5/10**6), td(microseconds=-1)) + eq(td(seconds=1/2**7), td(microseconds=7813)) + eq(td(seconds=-1/2**7), td(microseconds=-7813)) # Rounding due to contributions from more than one field. us_per_hour = 3600e6 @@ -1842,8 +1844,8 @@ class TestDateTime(TestDate): 18000 + 3600 + 2*60 + 3 + 4*1e-6) def test_microsecond_rounding(self): - for fts in [self.theclass.fromtimestamp, - self.theclass.utcfromtimestamp]: + for fts in (datetime.fromtimestamp, + self.theclass.utcfromtimestamp): zero = fts(0) self.assertEqual(zero.second, 0) self.assertEqual(zero.microsecond, 0) @@ -1874,6 +1876,12 @@ class TestDateTime(TestDate): t = fts(0.9999999) self.assertEqual(t.second, 1) self.assertEqual(t.microsecond, 0) + t = fts(1/2**7) + self.assertEqual(t.second, 0) + self.assertEqual(t.microsecond, 7813) + t = fts(-1/2**7) + self.assertEqual(t.second, 59) + self.assertEqual(t.microsecond, 992187) def test_insane_fromtimestamp(self): # It's possible that some platform maps time_t to double, diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py index 590425a..75ab666 100644 --- a/Lib/test/test_time.py +++ b/Lib/test/test_time.py @@ -655,7 +655,7 @@ class TestPytime(unittest.TestCase): pytime_object_to_time_t, invalid, rnd) @support.cpython_only - def test_timespec(self): + def test_object_to_timespec(self): from _testcapi import pytime_object_to_timespec # Conversion giving the same result for all rounding methods @@ -666,7 +666,7 @@ class TestPytime(unittest.TestCase): (-1, (-1, 0)), # float - (-1.2, (-2, 800000000)), + (-1/2**7, (-1, 992187500)), (-1.0, (-1, 0)), (-1e-9, (-1, 999999999)), (1e-9, (0, 1)), @@ -693,7 +693,7 @@ class TestPytime(unittest.TestCase): (1.1234567890, (1, 123456789), FLOOR), (1.1234567899, (1, 123456789), FLOOR), - (-1.1234567890, (-2, 876543211), FLOOR), + (-1.1234567890, (-2, 876543210), FLOOR), (-1.1234567891, (-2, 876543210), FLOOR), # Round towards infinity (+inf) (1.1234567890, (1, 123456790), CEILING), @@ -1155,7 +1155,7 @@ class TestOldPyTime(unittest.TestCase): self.assertRaises(OverflowError, pytime_object_to_time_t, invalid, rnd) - def test_timeval(self): + def test_object_to_timeval(self): from _testcapi import pytime_object_to_timeval # Conversion giving the same result for all rounding methods @@ -1167,7 +1167,8 @@ class TestOldPyTime(unittest.TestCase): # float (-1.0, (-1, 0)), - (-1.2, (-2, 800000)), + (1/2**6, (0, 15625)), + (-1/2**6, (-1, 984375)), (-1e-6, (-1, 999999)), (1e-6, (0, 1)), ): @@ -1225,7 +1226,7 @@ class TestOldPyTime(unittest.TestCase): (-1.0, (-1, 0)), (-1e-9, (-1, 999999999)), (1e-9, (0, 1)), - (-1.2, (-2, 800000000)), + (-1/2**9, (-1, 998046875)), ): with self.subTest(obj=obj, round=rnd, timespec=timespec): self.assertEqual(pytime_object_to_timespec(obj, rnd), diff --git a/Python/pytime.c b/Python/pytime.c index d226389..0364473 100644 --- a/Python/pytime.c +++ b/Python/pytime.c @@ -82,10 +82,6 @@ _PyTime_DoubleToDenominator(double d, time_t *sec, long *numerator, volatile double floatpart; floatpart = modf(d, &intpart); - if (floatpart < 0) { - floatpart += 1.0; - intpart -= 1.0; - } floatpart *= denominator; if (round == _PyTime_ROUND_HALF_UP) @@ -98,6 +94,10 @@ _PyTime_DoubleToDenominator(double d, time_t *sec, long *numerator, floatpart -= denominator; intpart += 1.0; } + else if (floatpart < 0) { + floatpart += denominator; + intpart -= 1.0; + } assert(0.0 <= floatpart && floatpart < denominator); *sec = (time_t)intpart; -- cgit v0.12